J/A+A/699/A356 Chemical abundances of 37 Sagittarius stars (Liberatori+, 2025)
A chemical close-up of the main body of the Sagittarius dwarf galaxy.
Liberatori A., Alvarez Garay D.A., Palla M., Mucciarelli A., Bellazzini M.,
Romano D.
<Astron. Astrophys. 699, A356 (2025)>
=2025A&A...699A.356L 2025A&A...699A.356L (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, nearby ; Stars, giant ; Abundances ; Optical
Keywords: Galaxies: abundances - Galaxies: dwarf - Local Group
Abstract:
We present the chemical composition of a sample of 37 red giant branch
(RGB) stars belonging to the main body of the remnant of the
Sagittarius (Sgr) dwarf spheroidal galaxy. All stars were observed
with the FLAMES-UVES high-resolution spectrograph. Twenty-three new
targets were selected along the blue side of the RGB of Sgr, but
outside the galaxy stellar nucleus, in order to avoid contamination by
the stars of the metal-poor globular cluster M54. Additionally, we
re-analysed archival spectra of 14 targets located on the red RGB. For
this sample, we derive the abundances of 21 chemical species (from
oxygen to europium) representing different nucleosynthetic sites. The
sample covers a large range of metallicities, from [Fe/H]~-2 to
~-0.4dex, and we can identify the transition between the enrichment
phases dominated by core-collapse and Type Ia supernovae. The observed
[alpha/Fe] trend suggests a knee occurring at [Fe/H]~-1.5-1.3dex,
compatible with the rather low star formation efficiency of Sgr. At
lower [Fe/H], Sgr stars exhibit a chemical composition compatible with
Milky Way stars of similar [Fe/H]. The only relevant exceptions are
[Mn/Fe], [Zn/Fe], and [Eu/Fe]. Instead, at [Fe/H] higher than
-1.5/-1.3dex, the chemical pattern of Sgr significantly deviates from
that of the Milky Way for almost all the elements analysed in this
study. Some of the abundance patterns reveal a lower contribution by
very massive stars exploding as hypernovae (e.g. [Mn/Fe], [Zn/Fe]), a
higher contribution by sub-Chandrasekhar progenitors of Type Ia
supernovae (e.g. [Ni/Fe]), and a high production efficiency of rapid
neutron-capture elements ([Eu/Fe]).
Description:
Table A1 includes identification number from Gaia Data Release 3 and
all the chemical abundance ratios and corresponding uncertainties.
Table A2 includes measured abundances.
99.99 stands for no measured abundance.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 106 37 Sagittarius spectroscopic targets: photometric
data, atmospheric parameters, [Fe/H] and RVs
tableb1.dat 355 37 Main information of the observed targets
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See also:
I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 19 I19 --- GaiaDR3 Star Name (Gaia DR3 source_id)
21- 35 F15.11 deg RAdeg Righ ascension (ICRS) at Ep=2016.0
37- 51 F15.11 deg DEdeg Declination (ICRS) at Ep=2016.0
53- 59 F7.4 mag Gmag Gaia DR3 G magnitude
61- 66 F6.4 mag BP-RP Gaia DR3 BP-RP colour
68- 71 I4 K Teff Effective temperature
73- 76 F4.2 [cm/s2] logg Surface gravity
78- 81 F4.2 km/s vturb Microturbulent velocity
83- 87 F5.1 km/s RV Radial velocity (Errors are 0.1km/s)
89- 93 F5.2 --- [Fe/H] Metallicity
95- 98 F4.2 --- e_[Fe/H] Metallicity error
100-106 I7 --- M21 ? Identification number of the stars in common
with Minelli et al. (2021ApJ...910..114M 2021ApJ...910..114M)
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Byte-by-byte Description of file: tableb1.dat
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Bytes Format Units Label Explanations
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1- 19 I19 --- GaiaDR3 Star Name (Gaia DR3 source_id)
23- 27 F5.2 --- [FeI/H] Abundance relative to the Sun for FeI
31- 35 F5.2 --- e_[FeI/H] Uncertainty on the abundance for FeI
39- 43 F5.2 --- [OI/Fe] ?=99.99 Abundance relative to the Sun for OI
47- 51 F5.2 --- e_[OI/Fe] ?=99.99 Uncertainty on the abundance for OI
55- 59 F5.2 --- [NaI/Fe] ?=99.99 Abundance relative to the Sun for NaI
63- 67 F5.2 --- e_[NaI/Fe] Uncertainty on the abundance for NaI
71- 75 F5.2 --- [MgI/Fe] Abundance relative to the Sun for MgI
79- 83 F5.2 --- e_[MgI/Fe] Uncertainty on the abundance for MgI
87- 91 F5.2 --- [AlI/Fe] ?=99.99 Abundance relative to the Sun for AlI
95- 99 F5.2 --- e_[AlI/Fe] ?=99.99 Uncertainty on the abundance for AlI
103-107 F5.2 --- [SiI/Fe] ?=99.99 Abundance relative to the Sun for SiI
111-115 F5.2 --- e_[SiI/Fe] ?=99.99 Uncertainty on the abundance for SiI
119-123 F5.2 --- [CaI/Fe] Abundance relative to the Sun for CaI
127-131 F5.2 --- e_[CaI/Fe] Uncertainty on the abundance for CaI
135-139 F5.2 --- [ScII/Fe] Abundance relative to the Sun for ScII
143-147 F5.2 --- e_[ScII/Fe] Uncertainty on the abundance for ScII
151-155 F5.2 --- [TiI/Fe] Abundance relative to the Sun for TiI
159-163 F5.2 --- e_[TiI/Fe] Uncertainty on the abundance for TiI
167-171 F5.2 --- [VI/Fe] Abundance relative to the Sun for VI
175-179 F5.2 --- e_[VI/Fe] Uncertainty on the abundance for VI
183-187 F5.2 --- [CrI/Fe] Abundance relative to the Sun for CrI
191-195 F5.2 --- e_[CrI/Fe] Uncertainty on the abundance for CrI
199-203 F5.2 --- [MnI/Fe] Abundance relative to the Sun for MnI
207-211 F5.2 --- e_[MnI/Fe] Uncertainty on the abundance for MnI
215-219 F5.2 --- [CoI/Fe] Abundance relative to the Sun for CoI
223-227 F5.2 --- e_[CoI/Fe] Uncertainty on the abundance for CoI
231-235 F5.2 --- [NiI/Fe] Abundance relative to the Sun for NiI
239-243 F5.2 --- e_[NiI/Fe] Uncertainty on the abundance for NiI
247-251 F5.2 --- [CuI/Fe] ?=99.99 Abundance relative to the Sun for CuI
255-259 F5.2 --- e_[CuI/Fe] Uncertainty on the abundance for CuI
263-267 F5.2 --- [ZnI/Fe] ?=99.99 Abundance relative to the Sun for ZnI
271-275 F5.2 --- e_[ZnI/Fe] Uncertainty on the abundance for ZnI
279-283 F5.2 --- [ZrI/Fe] ?=99.99 Abundance relative to the Sun for ZrI
287-291 F5.2 --- e_[ZrI/Fe] ?=99.99 Uncertainty on the abundance for ZrI
295-299 F5.2 --- [BaII/Fe] Abundance relative to the Sun for BaII
303-307 F5.2 --- e_[BaII/Fe] Uncertainty on the abundance for BaII
311-315 F5.2 --- [LaII/Fe] ?=99.99 Abundance relative to the Sun for LaII
319-323 F5.2 --- e_[LaII/Fe] ?=99.99 Uncertainty on the abundance for LaII
327-331 F5.2 --- [NdII/Fe] Abundance relative to the Sun for NdII
335-339 F5.2 --- e_[NdII/Fe] Uncertainty on the abundance for NdII
343-347 F5.2 --- [EuII/Fe] Abundance relative to the Sun for EuII
351-355 F5.2 --- e_[EuII/Fe] Uncertainty on the abundance for EuII
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Acknowledgements:
Alessio Liberatori, aliberatori(at)phys.uoa.gr
(End) Patricia Vannier [CDS] 03-Jul-2025